1. Field of the Invention
The present invention relates to vibration or shock sensors. More particularly, the invention relates to a vibration sensor that more effectively measures certain characteristics of vibrations and shocks to determine the cause thereof.
2. Description of the Prior Art
Vibration or shock sensors are commonly used in alarm systems to activate an alarm whenever the devices to which they are attached are touched, moved, or otherwise vibrated. For example, vibration sensors are commonly placed in windows of buildings to sense glass breakage and in car alarm systems to detect vehicle tampering. Additionally, the UL now requires high security safe and vault alarm systems to include vibration sensors.
Prior art vibrations sensors typically utilize ball or reed-type switches that open or close a contact when they are vibrated or moved. Unfortunately, these types of sensors often cause false alarms because they cannot distinguish between vibrations that occur due to normal causes and those that occur due to attempted unauthorized entry. For example, when placed in windows or doors, prior art sensors will often trigger an alarm when someone merely knocks on the window or door or when the window or door is vibrated due to thunder or wind as well as when someone attempts to illicitly gain entry through the window of door. This is because prior art vibration sensors only sense vibrations by detecting the opening and/or closing of a contact, which will occur regardless of the magnitude and/or duration of the vibrations.
There is therefore a need for an improved vibration sensor that more effectively distinguishes between various causes of vibrations.